Hi bbmouse,
While I can’t help you decide on which mattress is the best match for you in terms of PPP (I can’t feel what you feel or see you on the mattress) or which one would be the best “value” for you for an exchange (which would depend a great deal on which one was the most suitable for you and how comfortable you are with any additional costs) … I can certainly add a few comments that may help.
This isn’t unusual because it can take more time for the higher density memory foam in the Contour series to soften with body heat but once it softens they are often “soft enough” although each person will have their own preferences which will also depend on their body type and sleeping positions.
This is fairly typical of any higher density memory foam mattress with a relatively thin cover. While the cover may wick moisture … the moisture really has nowhere to go because the part of the mattress that is under you isn’t exposed to the air. If you move around then the moisture can evaporate but this may not be meaningful if you are sleeping in the same position for longer periods of time.
Memory foam is a temperature sensitive material and while different types of memory foam can be more or less temperature sensitive than others … all of them will be affected by temperature to some degree. If you sleep on a memory foam mattress for “long enough” for your body heat to soften the foam underneath you then the room temperature will make less difference to the foam directly underneath you (although the foam will take longer to soften in colder rooms) but the parts of your mattress that are more exposed to the room temperature will tend to be firmer when you change position and will once again take a little longer to soften underneath you.
The effect of gel in memory foam will vary depending on the percentage of gel and how the gel is added to the memory foam but in most cases the effect of gel is more temporary and will only stay cooler until temperatures equalize after which the insulating properties of the memory foam will become more dominant and become warmer. There is more about gel memory foams in post #2 here.
There is more about different types of mattress protectors and their effect on sleeping temperature in post #89 here. The effect of the mattress protector they are suggesting would depend on which type it was. Your sheets can also have a noticeable effect on sleeping temperature and natural fibers (such as cotton or linen more linen) or semi-synthetic fibers such as bamboo or other viscose fabrics will tend to wick or store moisture better than synthetic fibers such as polyester. In many cases the mattress protector and sheets you are using can make “enough” of a difference for many people that would otherwise sleep warmer on memory foam but there will still be some that will tend to sleep warmer on any type of softer memory foam. There is more about all the variables that can affect sleeping temperature in post #2 here and the posts it links to.
I don’t know the specifics of your platform but in general terms if it has a firm non flexing surface with good center support to the floor it would generally work well in practical terms but this may not be “good enough” for Tempurpedic and I would also be aware that Tempurpedic specifies a solid surface foundation in their warranty (see here) and they are rather vague about their other requirements except to say that you may need to “prove” that your foundation is suitable for their mattress if you ever have a warranty claim if you use any foundation other than theirs. At the very least it’s clear that you would need suitable solid surface support system. If you have an adjustable bed with a solid surface then there would be no doubt that it would be suitable by their standards.
If you do decide to go with an adjustable base then there is more information in post #3 here and the adjustable bed thread that may be helpful because there are some better value options than the ones that Tempurpedic sells that have very similar functions but aren’t “branded” as a Tempurpedic.
It seems like you are making some good progress with your research although I know that you have some “difficult” choices to make.
Phoenix